Detachable practice mine section



April 23, 1963 Filed July 19. 1960 FIGJ.

FIGA.

F. E. BUTLER ET AL DETACHABLE PRACTICE MINE SECTION 2 Sheets-Sheet 1 W07 lnvg O :0 mg

INVENTORS V. G. COSTLEY,F. E. BUTLER, L. C. LUH,C. W. DOVELL,

D. M. LESLIE April 1963 E. E. BUTLER ET AL 3,086,464

DETACHABLE PRACTICE MINE SECTION Filed July 19. 1960 2 Sheets-Sheet 2 FIG.2.

INVENTORS.

V. G. COSTLEY, F. E. BUTLER,

L. C. LUH ,C.W.DOVELL,

D. M.LESL|E 4 ATTORNEYS.

3,086,464 DETACHABLE PRACTECE MHQE SECTIQN Francis E. Butler, Washington, D.C., and (liar-is Dovell and Donaid M. Leslie, Silver Spring, and Vivian G. Costley, T akoxna Park, Md, and La Verne C. Lula,

Alexandria, Va., assignors to the United States of America as represented by the Secretary of the Navy Filed .luiy 19, 1960, Ser. No. 43,967 Claims. (Cl. 192-16) (Granted under Title 35, US. (lode (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a drill section to be used in conjunction with a mine for drill purposes and more particularly to :a visual signal device for indicating actuation of the mine.

Broadly speaking, drill mines fall into one of three nominal categories: dummy, realistic recoverable, and realistic expendable. The term realistic means operationally equivalent or nearly equivalent to a service mine except without main explosive loading.

The present invention may be utilized in either the realistic expendable or the realistic recoverable type of mine. It is very desirable to provide the crews of the submarines, surface vessels and airplanes a realistic dummy mine for practice in handling, loading and for planting.

It is also desirable to provide a realistic drill mine for fleet war games to train crews in assembly, planning, laying, sweeping and for the general purpose of acquainting the fleet with mine warfare capabilities.

A high degree of realism is required and it is important that the indication of firing of the mine he as dramatic and impressive as possible.

The present invention overcomes the disadvantages of the prior art by providing a practice section that will replace the explosive section of the mine and which includes a signaling device which is operated by the firing mechanism of the mine.

It is an object of this invention to provide a practice mine section of identical weight as the explosive section which it replaces.

it is another object to provide a practice mine section that is interchangeable with the explosive section of the mine.

It is still another object to provide a float to be used with a mine for drill purposes, the float including visual signaling apparatus.

A further object is to provide a float to be used with a drill mine in which the signaling element is released in response to actuation of the mine firing circuit.

Further objects and the entire scope of the invention will become more clearly apparent in the following detailed description and in the appended claims. The accompanying drawings display the general construction and operational principles of the invention. It is to be understood, however, that the drawings are furnished only by way of illustration and not in limitation, wherein:

FIG. 1 discloses a plan view, partly in section of the mine and mine anchor;

FIG. 2 discloses a sectional view of the practice mine section;

FIG. 3 discloses a detailed sectional view of the arming bar and the release Wire according to one embodiment of the invention; and

FIG. 4 discloses the firing mechanism of the float signal.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a mine $85,464 Patented Apr. 23, 1963 having an anchor section 11 similar, for example, to that recited in Patent 2,789,503, a mechanism section 12 which may be similar to that recited in Patent 2,781,723, and a drill section 13. The drill section 13 is identical in size and weight with an explosive section normally utilized on this mine. Just prior to launching the mine safety screw 15 is removed. The mine may be laid by ejecting it from the torpedo tube of a submarine, by air drop or by various other methods from surface vessels. Upon being ejected from a torpedo tube, for example, safety rod 16 is thrown off by spring biased hydroswitches 17 and 2t releasing the switches for operation.

The mine drops to the floor of the body of water be cause of the heavy anchor section 11. One of the hydroswitches closes at a predetermined depth thereby energizing a clock delay device. After a predetermined delay period the mechanism section and drill section are released from the anchor section by the clock mechanism (not shown but clearly described in Patent 2,789,503). The mechanism section and the drill section float toward the surface of the water until stopped by actuation of a locking mechanism located in the anchor, not shown but described in Patent 2,789,503 thereby locking the mechanism section to the anchor cable.

Arming wire 18 shown in FIG. 2 is attached to the anchor and acts as !a cotter pin for spring member 19 which holds the signal cover 20 in place. Release of the anchor section 11 from the mechanism section 12 removes arming wire .18 from a hole in bolt 9. Removal of arming wire 18 results in spring 19 immediately disengaging itself from the mine due to the biased position over the signal cover 20. The cover continues to remain in place because of the hydrostatic pressure on the outside of the cover.

The mechanism section and the drill section continue to rise toward the surface of the water until the locking mechanism is actuated. The locking mechanism is responsive to a decrease in pressure only. Upon actuation of the locking mechanism a locking member not shown is actuated in the mechanism section thereby locking the anchor cable so that the mine sections continue to float in a submerged state at this predetermined depth.

The drill section of the mine has an outside casing and hydrostatic switches identical to an explosive section. The explosive charge inside the chamber has been replaced by a float chamber 22 and a heavy inert material 23 for ballast such as cement or other dense material.

The float chamber 22 houses a float 24 with a signal 25 located therein. The float has a hook member 26 held in slot 27 by an explosive bolt 28.

When a vessel passes within lethal range, a magnetometer of the type well known in the art, located in the mechanism section actuates the firing circuit of the mine, the firing circuit ordinarily used to fire the detonator energizes the explosive bolt 28 through adapter cable 32. The explosive bolt splits into two parts, one portion being ejected into cavity 29, the other portion being ejected out through an aperture 30 in the housing, thereby allowing water to enter the chamber housing. The explosive bolt also shears a plastic rod 31 which controls the signal energizer.

As the water enters the float chamber 22, it surrounds float 24- thereby causing the hydrostatic pressure inside to be equal to the outside pressure. After the explosive bolt holding the float is fired thereby releasing the float 24, the float spring 33 forces the float against cover member 20. As the hydrostatic pressures equalize the spring 33 forces the float out of the chamber and the cover member 20 falls to one side but is held on the mine for reuse by flexible wire 34-. The float is sufficiently buoyant so that it rises to the surface of the water.

apsaaea The signal float 24 consists of a cylindrical body 35, for example, rubber coated wood to which is attached with straps 47 on ogive-shaped sheet aluminum cover 36 on one end and a flange with a hook 26 and shroud ring 37 on the other end. A hole 38 is located axially in the nose of the cover to emit the flare and smoke. This hole is sealed with a special blow out plug 39. The plug is removed by a small gas pressure from inside the chamber.

A sinking mechanism 55 for sinking the expended float consists of a chamber 40 with an orifice 41 located on one side of the signal float which will open after a time delay to the sea water for sinking the signal. The orifice 41 is closed with a soluble doughnut-shaped washer 42 which is held in place by a doughnut-shaped set screw 43. The sea water enters a hole in the doughnut-shaped set screw and washer and slowly dissolves the soluble washer. When the soluble washer is dissolved orifice 41 is opened and the sea water enters chamber 40 causing the signal to sink to the bottom. While the signal is located in the mine the orifice 41 is covered by a cap 44 which is biased by a spring 45-. The cap is removed from the signal float as soon as the hydrostatic pressure on the cap 44 is less than the pressure of spring 45. As soon as the cap 44 is removed, the washer 42 is exposed to the sea water and begins to dissolve.

The shroud ring 37 guides the signal float as it ascends through the water and helps to hold it in an upright position after it reaches the surface.

FIG. 4 discloses the actuating device for the float signal. The device is held immobile until the plastic rod 31 is sheared by the explosive bolt. After the plastic rod is sheared the spring member 48 exerts a pressure against the cup-shaped member 49 and diaphragm 50. The water pressure is exerted on the bellows from the outside approximating the spring pressure. As the float begins to rise the water pressure will be reduced allowing the spring to force the cup-shaped member and bellows away from pin member 51. As the cup-shaped member 4-9 continues to move the side portions of member 49 move past the recesses 54 in member 52 that hold locking balls 53. The balls 53 normally lock the firing pin 51 in a potential firing position. As the side portions of the cup-shaped member 49 move past the recess 54 in member 52 the looking balls 53 are cammed out into the space vacated by member 49 thereby releasing the firing pin 51 which is then forcibly driven by spring 48 into a percussion cap, not shown, for setting off a pyrotechnic delay train to the signal.

The pyrotechnic delay train has a sufficient delay to allow the float to reach the surface before the main signal is actuated. The signal may be of the kind well known in the art such as a pyrotechnic or a water-reactive chemical which produces a flammable gas, or some other form of display, such as a gas-filled colored balloon.

If night-time indication is required, some form of light or flame may be included with the balloon.

Briefly, the operation of the disclosed drill mine will now be described as follows: a clock mechanism with the mine is set for the desired time delay and the mine is laid. A hydrostatic pressure switch starts the clock mechanism as the mine drops to the ocean floor. At the expiration of the predetermined period of time a switch is closed and the anchor is released. The mechanism section and drill section are released and the arming wire is removed. These two sections float toward the surface uncoiling the anchor cable as they go. At another predetermined depth a counting mechanism located in the anchor actuates a explosive driver through the electric transmission line. The explosive driver drives a wedge against the anchor cable locking it in place. The mine mechanism continues to float at this water depth in the armed position.

If a vessel passes within lethal range the magnetometer actuates the firing circuit of the mine and the firing circuit detonates the explosive bolt shearing the plastic rod, flooding the chamber and releasing the float.

The float begins to rise to the surface and the diminishing pressure allows the hydrostatically operated firing mechanism to begin operation. At a shallow depth a spring-loaded firing pin is propelled into a percussion primer in the signal element mounted in the float which causes flare and smoke emission. As soon as a slight gas pressure is built up in the chamber the blowout plug is removed. Diminishing pressure also allows the spring to remove the protective cap over the soluble washer. The soluble washer dissolves uncovering a hole for admission of water into the float chamber to cause it to sink.

It can be seen that this device not only provides a realistic drill mine but that the mine may be disassembled for storage; for example, the anchor, mechanism compartment and the drill section may be stored in separate areas.

The mine mechanism may be tested and maintained prior to use without the danger of an explosion thus providing a more dependable mine unit.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A drill mine for providing realistic training in maintaining, handling and laying of mines comprising a releasable anchor section, a mechanism section having one end normally attached to said anchor section, a drill section integrally connected to the other end of said mechanism section, means located in said anchor section for releasing said anchor section and mooring said mechanism section and drill section at a predetermined submerged level, detector means located in said mechanism section for gen erating a voltage signal whenever a ship passes within lethal range of said mine, visual signal means normally located in said drill section and released by the voltage actuation of said detector means for providing a visual signal to indicate the operation of the mine.

2. The drill mine of claim 1 wherein said drill section is interchangeable with an explosive section having the same size, shape and weight.

3. The drill mine of claim 1 wherein the visual signal means located in said drill section is a float, an electroresponsive bolt connected to said detector means for normally holding said float in said drill section, a combustible means located in said float which is activated upon release of said float and provides a visual signal upon reaching the water surface, whereby said float is released upon actuation of said electroresponsive bolt by said detector means.

4-. A drill mine for providing realistic training in handling, laying and sweeping mines comprising an anchor section having an anchor normally locked therein, a drill section, a mechanism section connected between said anchor and drill sections, mooring means located in said anchor section for unlocking the anchor and mooring the mine at a preset depth, detector means located in said mechanism section for generating a voltage signal when a vessel passes within lethal range of the mine, signal means located in said drill section and responsive to the voltage signal generated by said detector means for providing a visual indication that the mine has operated, said drill section of the mine being similar in size, shape and weight to an explosive section, said signal means in said drill section including a float chamber, a float, an explosive bolt connected to said detector means for normally holding said float in said float chamber, a container disposed in said float, visual means releasably located in said container for producing a visual signal after release whereby said detector means produces a voltage signal energizing said explosive bolt thereby releasing said float and energizing said visual means in said container for providing a visual signal.

5. A drill mine for providing realistic training in han- 5 dling, laying and sweeping mines comprising an anchor section having an anchor normally locked therein, a drill section, a mechanism section connected between said anchor and drill sections, mooring means located in said anchor section for unlocking the anchor and mooring the mine at a preset depth, detector means located in said mechanism section for generating a voltage signal when a vessel passes within lethal range of the mine, signal means located in said drill section and responsive to the voltage signal generated by said detector means for providing a visual indication that the mine has operated, said drill section having the same size, shape and weight as an explosive section interchangeable therewith thereby providing realistic training in handling of a mine, said signal means in said drill section including a float chamber, a float within said float chamber, an explosive bolt locking said float within said chamber, a visual signal means including a container in said float for providing a visual signal when the visual signal means is actuated, whereby said detector means generates a signal exploding the explosive bolt, thereby unlocking the float and energizing said visual signal means.

References Cited in the file of this patent UNITED STATES PATENTS 2,706,948 Turlay Apr. 26, 1955 2,775,939 Fogal Jan. 1, 1957 2,949,853 Vogt Aug. 23, 1960 

1. A DRILL MINE FOR PROVIDING REALISTIC TRAINING IN MAINTAINING, HANDLING AND LAYING OF MINES COMPRISING A RELEASABLE ANCHOR SECTION, A MECHANISM SECTION HAVING ONE END NORMALLY ATTACHED TO SAID ANCHOR SECTION, A DRILL SECTION INTEGRALLY CONNECTED TO THE OTHER END OF SAID MECHANISM SECTION, MEANS LOCATED IN SAID ANCHOR SECTION FOR RELEASING SAID ANCHOR SECTION AND MOORING SAID MECHANISM SECTION AND DRILL SECTION AT A PREDETERMINED SUBMERGED LEVEL, DETECTOR MEANS LOCATED IN SAID MECHANISM SECTION FOR GENERATING A VOLTAGE SIGNAL WHENEVER A SHIP PASSES WITHIN LETHAL RANGE OF SAID MINE, VISUAL SIGNAL MEANS NORMALLY LOCATED IN SAID DRILL SECTION AND RELEASED BY THE VOLTAGE 